Polyethylene thickened grease containing amides



Patented Nov. 10, 1970 3,539,516 POLYETHYLENE THICKENED GREASE CONTAINING AMIDES Harold C. Walters and Henry E. Alquist, Bartlesville,

kla., assignors to Phillips Petroleum Company, a corporation of Delaware No Drawing. Filed Nov. 25, 1968, Ser. No. 778,835 Int. Cl. C10m 5/20 US. Cl. 252-51.5 5 Claims ABSTRACT OF THE DISCLOSURE N-substituted- -hydroxycarboxylic acid amides are incorporated into polyolefin-thickened greases to reduce oil separation.

This invention realtes to lubricants and more particularly to bodied lubricants or greases.

Lubricant greases can be prepared from lubricating oils and soaps or metal salts of fatty acids as thickening agents. Greases prepared from lubricating oils and thickening agents other than soaps are also known. For example, US. Pat. No. 3,112,270 discloses soapless greases compounded from lubricating oils and high density ethylene polymers, which greases have excellent work stability, that is, the greases maintain desired consistency when subjected to mechanical working. However, with such soapless greases the oil tends to separate (bleed) therefrom during transportation and storage especially if the greases are subjected to extreme temperature conditions. While this is not a fatal defect, such oil separation or bleeding is undesirable.

It is, therefore, a principal object of this invention to provide soapless greases having a substantially reduced tendency to bleed.

We have discovered that bleeding of soapless, polyolefin-thickened greases can be substantially reduced by incorporation in the greases of small amounts of one or more N-substituted-y-hydroxycarboxylic acid amides. The additives which have been found effectiveto reduce bleeding can be represented by the general formula:

wherein R represents either hydrogen or a methyl group, R represents an aliphatic hydrocarbon radical (saturated or unsaturated) containing from to 30 carbon atoms, for example, decyl, undecyl, undecylenyl, dodecyl, tridecyl, tetradecyl, cetyl, myristolenyl pentadecyl, heptadecyl, hexadecenyl, octadecyl, octadecenyl, octadecadienyl, abietinyl, oleyl, elaidyl, octylbenzyl eicosyl triacontyl, and the like and combinations of such radicals; and wherein R represents either hydrogen or an alkyl group of from 1 to about 18 carbon atoms, for example, methyl, propyl, butyl, amyl, hexyl, nonyl, decyl dodecyl cetyl, octadecyl, and the like; and wherein the total number of carbon atoms constituting the groups in both R and R is a minimum of 10 and nor more about 40 carbon atoms.

The compounds characterized by the above formula and utilized in accordance with the present invention can be obtained by conventional methods such as the reaction of one mole of an organic primary amine, or mixtures of such amines, containing from 10 to about 30 carbon atoms with one mole of either gamma-butyrolactone or gammavalerolactone at a temperature of about 80-95 C. The amines have the formula \CH.NH2

where R and R have the values indicated above. Preferably, both R and R are hydrogen and R is formed from a mixture of saturated or unsaturated amine residues derived from naturally occurring fatty acids (by replacing the carboxyl group with a primary amine group) such as are obtained from coconut oil, soya oil, tallow, and the like which are commercially available (for example, under the brand name of Duomeens) Greases prepared in accordance with this invention comprise a lubricating oil of the type normally employed in formulating lubricant greases thickened with a high density polyolefin and one or more of the above-identified amides. Thus, the lubricating oil base can be a mineral, vegetable or animal oil or mixtures thereof. It is preferred that at least a major amount of the lubricating base oil be mineral in origin and most preferably a refined oil having a viscosity of about 50 to 240 SUS at 210 F. Less viscous lubricating oils resulting in lighter greases while heavier greases can be prepared from more viscous type oils, for example an oil having a viscosity of about to 240 SUS at 210 F. White mineral oil can be used to make non-staining greases which are particularly adapted for lubricating machinery in the textile and food industries. Paraffinic oils are preferred for the preparation of greases of low graininess.

The polyolefin thickeners employed in accordance with this invention are ethylene polymers having a density at 25 C. of at least 0.940 gram per cubic centimeter. Such ethylene polymers are disclosed in US. Pat. No. 3,112,- 270, and the disclosure therein is incorporated by reference herein. The density of these polymers generally will not exceed 0.970 although more dense, for example, polymers having a density of 1.00, can be used. The ethylene polymers which are employed include not only the homo polymer, polyethylene, but also copolymers of ethylene with olefins of high molecular weight, for example up to 8 carbon atoms per molecule, preferably containing no branching nearer the double bond than the 4-position. Examples of suitable comonomers include propylene, 1- butene, 2-butene,l-pentene, l-octene, 4-methyl-1-pentene, 4ethyl-1-pentene, 4-methyl-l-hexene, 6-methyl-l-heptene, 4-ethyl-1-hexene and the like. We prefer the copolymers of ethylene with propylene or l-butene. In general, ethylene makes up at least 95 weight percent of the copolymer. In forming such a polymer the monomer feed to the polymerization zone will ordinarily be at least percent by weight ethylene. As the percent of ethylene in the copolymer is decreased the density of the polymer likewise is decreased so that the density limitation can be used as an indication of copolymer composition. In any event, the density of the copolymer or homopolymer employed will be at least 0.940.

In general, the amount of ethylene polymer employed to thicken the lubricating oil so as to produce desired greases is in the range of from about 1.0 to 20 weight percent of the finished grease depending upon the specific oil and polymer used and upon the desired hardness of the grease. Preferably the polymer concentration in the finished grease will be in the range of 7 to 15 weight percent.

The amide additive is employed in the finished grease in accordance with this invention in amounts suitable to control the oil separation (bleeding) to a satisfactory level. These amounts are generally in the range from about 0.1 to about 5, preferably 0.5 to about 2 weight percent of the finished grease. However, amounts below and above these specified ranges can be used, if desired.

It should be understood that other materials normally used in greases can be added to the compositions of our invention. For example, various additives such as rust inhibitors, antioxidants, and the like are frequently included. Other modifiers such as fillers, pigments, perfumes and the like can be used. Examples of such materials include propylenediamine, phenylalpha-naphthylamine, phenothiazine, mica, asbestos, powdered lead, powdered zinc, talc, alumina, zinc oxide, titanium dioxide, mont morillonite, attapulgite, molybdenum disulfide, organophilic montmorillonites (Bentones), calcium carbonate, basic lead carbonate, calcium silicate, graphite, nitrobenzene, carbon black and the like. Generally, the amount of these modifiers is less than about percent of the total weight of the grease.

The soapless, polyethylene-thickened greases of the present invention are compounded, in general, by conventional methods such as those taught in United States Patent 3,112,270. Thus, the solid polymer is dispersed in the lubricating oil which has been heated to about 325 to 450 F. and generally above 380 F. for a period of time required to form a satisfactory polymer-oil dispersion. Usually, the polymer is adequately dispersed within about 1 to 60 minutes. The amide additive, as well as other conventional grease additives, is blended in with the grease during this polymer dispersion operation.

In addition to the high temperature polymer dispersion and additive incorporation step, the greases are generally milled to improve their properties. In this milling operation the polymer-oil-additive dispersion described above is cooled to a temperature between about 170 and 210 F. and subjected to a severe agitation which produces substantial shearing in the mixture. Preferably the grease milling is carried out in a colloid mill operated at high speeds and with relatively close clearances. Such grease milling is conventional and known in the art.

The following are representative examples of greases prepared in accordance with this invention.

Grease A: Wt. percent Mineral lubricating oil (190 SUS at 210 F.) 88.0 Polyethylene (Density 0.95) 8.0 Reaction product of N-decylamine with 'y-butyrolactone 1.0 Rust inhibitor 1.5

Antioxidant 1.5

Grease B:

Mineral lubricating oil 160 SUS at 210 F.) 76.2 Polyethylene (Density 0.976) 15.0 Reaction product of octadecylamine with 'y-butyrolactone 2.0 Rust inhibitor 1.2

Antioxidant 2.0 Extreme pressure additive 3.6

Grease C:

Naphthenic oil (75-95 SUS at 210 F.) 77.5 Polyethylene (Density 0.96) 12.4

Amide additive (Reaction product of 86.1 grams of 'y-butyrolactone with 274 grams of a mixture of amines: hexadecylamine 10%, octadecylamine 10%, octadecenylamine 35%, and octadecadienylamine 45%) Filler (Zinc oxide) Rust inhibitor 1.8

Antioxidant 2.0

4 Grease D:

Parafiinic oil (210 SUS at 210 F.) 77.1 Polyethylene (Density 0.94) 16.0

Amide additive (Reaction product of 0.2 mole of 'y-valerolactone and 0.2 mole of a mixture of ailphatic primary amines derived from soya oil fatty acids) 0.8 Antioxidant 2.5 Rust inhibitor 1.6 Filler (carbon black) 2.0

Grease E:

Refined lubricating oil SUS at 210 F.)

derived from Mid-Continent crude 89.46 Polyethylene (Density -0.960, melt index -5.0) 9.00 Rust inhibitor (Parabar 448, Enjay Co.) 0.04 N-coco-y-hydroxybutyramide (Butoxyne 160,

General Aniline & Film Corp.) 1.50

Grease F:

Refined lubricating oil 110 SUS at 210 F.)

derived from Mid-Continent crude 89.21 Polyethylene (Density -0.960, melt index -5.0) 9.00 Rust inhibitor (Parabar 448, Enjay Co.) 0.04 N-coco-v-hydroxybutyramide (Butoxyne 160,

General Aniline & Film Corp.) 1.50 Antioxidant (di-tertiarybutylparacresol) 0.25

Grease G:

Refined lubricating oil (110 SUS at 210 F.)

derived from Mid-Continent crude 90.21

Polyethylene (Density-0.960 melt index -5.0) 9.00 Rust inhibitor (Parabar 448, Enjay Co.) 0.04 N-coco y-hydroxybutyramide (Butoxyne 160,

General Aniline & Film Corp.) 0.50 Antioxidant (di-tertiarybutyl-para-cresol) 0.25

The Butoxyne referred to in Greases E, F and G is a product for-med by reacting 'y-butyrolactone with a mixture of saturated and unsaturated primary amines derived from coconut oil.

The reduction in oil separation or bleeding by incorporation in greases of the amide additives disclosed herein is readily apparent by comparing the bleed test results according to the procedure, ASTM D 1472-60T. Using this test method Greases E, F and G were compared with Grease H which did not contain an amide additive. Grease H had the following composition:

Grease H: Wt. percent Refined lubricating oil (110 SUS at 210 F.)

derived from Mid-Continent crude 90.96 Polyethylene (Density-0.960, melt index Rust inhibitor (Parabar 448, Enjay Co.) 0.04

Greases E, F, G and H were prepared by simple blending of the ingredients in a cast iron pressure kettle at a temperature of about 350-400 F. The viscous liquid was then cooled to about 290 F and milled by passage through a Charlotte colloid mill. The air was removed from the grease while it was hot with the aid of a vacuum pump. Each of these four greases had essentally the same hardness, being in the range of an NLGI Grade 2 grease. The bleed test results are shown in Table I.

TAB LE I Oil separation, milliliters Time Grease E Grease F Grease G Grease H The data above clearly illustrate the beneficial effects of the invention additive in reducing oil separation. Each of the invention grease compositions E, F and G exhibited much less oil separation than did the comparative grease composition H which was identical except that it did not contain the bleed-controlling additive. These data also show that the bleed-controlling additive is effective even in the presence of other conventional grease additives.

Those modifications and equivalents which fall within the spirit of the invention are to be considered a part thereof.

We claim:

1. A lubricant comprising a major amount of lubricating oil thickened with an ethylene polymer having a density of at least 0940 gram per cubic centimeter at 25 C., and a minor bleed reducing amount of an amide of the formula wherein:

R is hydrogen or methyl,

R is an aliphatic hydrocarbon radical containing from 10 to 30 carbon atoms, and

R is hydrogen or an alkyl group of from 1 to 18 carbon atoms and wherein the total number of carbon atoms in R and R is in the range from 10 to 40.

2. A lubricant in accordance with claim 1, wherein the ethylene polymer thickener is employed in an amount of from about 1.0 to 20 weight percent of the lubricant and the amide is employed in an amount of from about 0.1 to 5 weight percent.

3. A lubricant in accordance with claim 1, wherein the ethylene polymer thickener is employed in an amount of from about 7 to 15 weight percent of the lubricant and the amide is employed in an amount of from about 0.5 to

2 weight percent.

4. A lubricant in accordance with claim 1, wherein the amide is N-coco-v-hydroxybutyramide.

5. A process of preparing a thickened lubricant com-.

position which comprises dispersing in a lubricating oil base at a temperature of from about 325 F. to 450 F. a thickening amount of ethylene polymer having a density of at least about 0.940 gram per cubic centimeter at 25 C. and a bleed reducing amount of amide of the formula 0 o R R-(h-CHzOHziiNHdH wherein:

R is hydrogen or methyl,

R is an aliphatic hydrocarbon radical containing from 10 to 30 carbon atoms, and

R is hydrogen or an alkyl group of from 1 to 18 carbon atoms and wherein the total number of carbon atoms in R and R is in the range from 10 to 40, to form a uniform dispersion, cooling said dispersion below the final thickened lubricant.

References Cited DANIEL E. WYMAN, Primary Examiner I. VAUGHN, Assistant Examiner US. Cl. X.R. 25259 mg UNI'IED s'rmn-zs PATENT OI I JTC-E CERTIFICATE 01;" CORRECTION Patent No- 3 5qq 516 Dated November 10, 1970 lnv nt'vfl HAROLD Q WALTERS and HARRY ALQ I It is certified Lhat error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 6,. line 22, after "the" insert dispersing temperature, and milling to make the-- SEGN'ED mu SEALED m2 1971 nm am Ir. Aitcsting Officer Commissioner of Pa el 

